What Causes My Car Engine to Overheat

I drive a 2003 Volkswagen Passat. Yesterday I wasdown the center of the radiator with your hand, it
making a long trip home and about 20 minutes into theshould remain pretty hot. If the bottom of the radiator is
trip the car said it was overheating. The coolant levelMUCH cooler than the top, you have a restriction in the
was fine, and as soon as we would pull over theradiator and you probably need to replace the radiator.
temperature would drop back to normal (before weSame scenario as above, with engine hot - if the top
even got to a complete stop.) Later in the trip itand the bottom of the radiator seem warm but not
stopped cooling down when we would pull over andHOT...I would replace the thermostat as a guess.
there was a sort of popping/gurgling noise thatSomething is not allowing the coolant to flow through
sounded like it was sort of behind the dash.Took it tothe system properly.
the mechanic today and they have cleaned theI would NOT expect a 3 year old car to have a
radiator, checked the head gasket, etc. and they arerestricted radiator (caused by rust or calcium deposits)
baffled.but a faulty thermostat is possible.
Any ideas?Your car is also equipped with an electric cooling fan
Hi there,located near the radiator, next time it runs hot pull over,
The VERY first thing that needs to be done is aget out of the vehicle with the engine running and
"cooling system pressure test" this will determine ifmake sure this electric fan is ON. It will come on when
there is a coolant leak in the system. You want tothe engine heats up and go off when not needed, you
check the coolant level INSIDE the radiator, not justmight also have another electric fan near the radiator
what is in the plastic jug on the side of the engine.that will be for the a/c compressor and should be on
This car is pretty new still, is it under warranty or arewhen the a/c is ON.
there high miles? Since you mentioned that it ran hotThe noise you hear could just be the coolant inside the
while you were driving, and as soon as you pulled overengine and the heater core (located inside the dash on
and slowed down the temperature returned tothe passenger side) boiling...which makes the sound
normal...my first thought would be that there is lack ofyou describe. Next time it runs hot, turn on the heater
coolant circulation. Low coolant level can also causefull blast, it will probably reduce the engine temperature
lack of circulation, so make sure the radiator is FULL.enough so you don't have to pull over.
If the coolant level is full, check the temperature of theOf course it only take a few seconds of severe
radiator - with the engine HOT. Caution, do not burnengine overheating to damage the engine, so when in
yourself!!! Start at the top of the radiator in the centerdoubt pull over and turn off the engine.
and feel it with your hand...it should be very hot, move